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New comparison from European Environmental Agency (EEA) on Trains versus Planes

Train or plane?

Two new studies from EEA draw new light on climate impacts and broader environment impacts from European passenger and freight transport. With the new reports we are again able to refer to recent European figures, when we are discussing the environmental impacts of a modal shift from planes to rail.

The new reports updates an old EEA study from 2014 which was already in 2019 declared for not-updated.

The first study (briefing) from EEA (A) is giving the greenhouse gas perspective for both passenger and freight transport. Study also the background paper from Fraunhofer ISI and CE Delft.

The second study (EEA report) (B) is giving a more broad environmental perspective. Here greenhouse gasses are complemented by air pollution and noise. And 20 selected cross border travels are compared.

Both studies have the same weaknesses, which will be mentioned below.

Overall conclusion from EEA

EEA (A) concludes: “Trains are the most efficient form of passenger transport in the EU, with GHG emissions per pkm that are only a fraction of most other modes.”

EEA (B) concludes on page 48: “An analysis of 20 city pairs shows that the environmental costs of rail travel are substantially lower than those of air travel.”

Both studies are suffering by weak sources

Railway statistic is rather poor. That means that it is not possible to separate occupancy rates related to those railway lines directly competing with aviation. Data are to some degree ‘polluted’ with other lines, running on less developed and less used destinations including evenings and other ‘not-top-tuned’ services.

Those routes that are compared are based upon strong business cases in aviation. That is fair enough. But data on occupancy will with weak railway data sets favour aviation with higher occupancy rates (aviation assumed to 80%) and much lower rates with trains. And how is it counted on rail? Many of these lines do not exist as highend-express lines today. So it is a mix of existing HSR and EC/IC/RE-trains, that goes behind the data. EEA mention rates of 66% (HSR) and 36% (IC/RE-trains).

The non-CO2 related effects of aviation is counted different in the two reports and stated wrong both places. But that is probably because the EU Commission to has chosen to do so!

On the non-CO2 radiative forcing effects of aeroplane emissions, both studies use a low RFI (or GWP) as 1,23 (in A) (since the background paper did not have access to the new data) or 1,7 (B) (with access to new data). The reports did hereby not use the direct outcomes of scientific recommendations published December 2020 (see later).

Study A

Figure 1

Click on the picture to get an enlargement!

Study A is probably giving airplanes occupancy rates very close to 100% (unfortunately unclear data), underestimating the climate impact, and comparing with a larger range of rail transport (GHG’es and occupancy rates) according to weak datasets from the railway sector.

Study B

The study is using 20 selected travels in Europe between two major cities with air connections and rail connections of which 7 are < 500 km, 7 are 500-750 km, and 6 are 750 – 1100 km. Distances are calculated as car distance, and rail distance is set to the same. Air distance is set to the shortest line between the two cities (which might be a little bit wrong).

What is the environmental cost in study B?
EEA has selected four elements, that they find comprises the environmental costs:

  • Noise
  • Air pollution
  • Fossil fuel consumption on the move
  • Fossil fuel production
  • Non-CO2 related climate impact related to aviation.

And all elements are calculated in EUR to make it possible to make an overall figure. See this conclusive figure 5.4 (page 55):

Figure 2

Click on the picture to get an enlargement!

To mix so different things as climate, air pollution and noise is a very difficult exercise.

  • How to calculate it correct?

It is very interesting but very hard. With all respect to noise and air pollution, we should focus alone on climate impact, as study A.

How is the aviation climate impact calculated?

In figure 5.4 (see above) the non CO2-related climate impact from burning jetfuel in the atmosphere (Radiative Forcing Index, RFI) is put on top with dark blue and with a uncertainty scale (thin line). The dark blue bar is representing a RFI of 1,7.

Longer flights are at higher altitude, so the study multiplies by numbers ranging from 1.27 for flights of 500km to 2.5 for those of more than 1,000km. (to aprox 3,000 km). Longer flights are not considered.

(In study A from November 2020 RFI is set to 1,23).

That is very strange figures and not endorsed by EASA. The overall European recommendation (December 2020) is RFI = 3,0 by Lee et al and endorsed by the EASA. Let’s have a look at the EASA report from December 2020, from where we quote:

A relatively new application of the GWP, referred to as ‘GWP*’, produces a better temperature-based equivalence of short-lived non-CO2 climate forcers than the traditional use of GWP by equating an increase in the emission rate of a Short Lived Climate Forcer with a one-off “pulse” emission of CO2. The GWP* is an example of a ‘flow-based’ method that represents both short-lived and long-lived climate forcers explicitly as ‘warming-equivalent’ emissions that have approximately the same impact on the global average surface temperature over multi-decade to century timescales (Allen et al., 2016; 2018; Cain et al., 2019). GWP*100 for net aviation impacts was calculated by Lee et al. (2020) for recent conditions. The CO2-warming-equivalent emissions based on this method indicate that aviation emissions are currently warming the climate at approximately three times the rate of that associated with aviation CO2 emissions alone.

It could be argued that temperature-based metrics, and the GWP*, are potentially more useful for temperature-based policy objectives such as the temperature targets of the Paris Agreement. They also provide a more physical basis of actual impacts than GWPs for SLCFs.

Quotes are from pages 35-36 in “FINAL REPORT Updated analysis of the non-CO2 climate impacts of aviation and potential policy measures pursuant to the EU Emissions Trading System Directive Article 30(4)

A German study from 2019 goes into details in relation to length of the journey what we need to do. It is J.D. Scheelhaase in Journal of Air Transport Management 75 (2019) pages 68-74 and in this study the RFI of 1,7 is justified for the short distances, but on 1000 km the RFI is rather 3,0 due to the travel in high altitudes. However EASA is not making any differentiation, so we stick to 3,0 both on 500 and 1000 km. flying distances.

EEA write that the factor of 1.7 relates to a 100-year GWP and comes from the same EASA study. But it is not to find in the EASA study and must be a “political modification” of some sort.

How are occupancy rates calculated?

Again we are facing some weaknesses with the EEA report.

Occupancy rates is in figure 5.4 set to

  • Aviation: 80%
  • Passenger car: 1 passenger (study A 1,6)
  • Highspeed train: 66%
  • Intercity train: 36%

The railway occupancy rates are calculated in the Fraunhofer and CE Delft paper from average no. with highspeed trains and European IC trains (seems to include regional trains as well). Since datasets on occupancy rates are not more specific due to poor data from the railway industry, we have to make modifications. Above figures can ONLY BE WRONG, since railway data are mixed among most profitable lines with a large proportion of less profitable lines. The lines of interest of competition with European aviation is the MOST PROFITABLE and most USED lines with the best chance of high occupancy rates.

With cars it is not likely that the average occupancy rate is 1,0 person per car on distances 500-1000 km in Europe. EEA is also mentioning 1,5, as they used in 2014 or 1,6.

Let us go with these occupancy rates: Aviation: 80%, passenger car: 1,5 passengers, all international trains competing with aviation 500 and 1000 km: 70%

Now, let us stick to grams of CO2 per passenger kilometer. EEA is not against further calculations based upon their figures. The price per emitted ton of CO2 is in the report study B set to 100 EUR , so figure 5.4 can hereby be re-calculated. Lets see where that will take us.

The more real figure of climate impact based on study B

This is the re-estimated figure 5.4 with the aviation climate impact in grams CO2e, as it should be, and corrected with comparable occupancy rates:

  • Average fossil car: 111 grams CO2e per passenger kilometer (occ. rate: 1,5)
  • Electric car: 26 grams CO2e (occ. rate: 1,5)
  • International High speed train: 18 grams CO2e (occ. rate: 0,7)
  • International conventional electric train: 12 grams CO2e (occ. rate: 0,7)
  • A320 on a 500 km journey: 340 grams CO2e (occ. rate: 0,8 and GWP 3,0)
  • A320 on a 1000 km journey: 270 grams CO2e (occ. rate: 0,8 and GWP 3,0)

So per kilometer journey on European distances the rail journey is in the range of 22-28 times more climate friendly than aviation.

Sorry to say: This diagram is not what we wanted. We wished for a EEA endorsed and widely accepted calculation on this matter. Since that is not the case, this re-calculation is the second option to take.

What difference does it make – as long as trains is more eco-friendly than planes?
Does it make any significant difference if trains are 5, 10 or 20 times more eco-friendly than planes? Yes it does. The margin will provide room for investments and subsidies all the time as long as market prices are not reflecting the real ecological footprint. With a factor 20 more climate friendly railways, it makes a sound economy to engage in large infrastructure investments and big get-trains-on-the-tracks subsidies to follow the green climate decisions.

Other observations

Night trains in study B
Night trains are mentioned at page 66: “The same applies for the (re-)introduction of night trains, which could offer a strategy to deal with longer rail travel times.”  And on page 68: “Another strategy to deal with longer rail travel times for longer distances (e.g. between 800 and 1 200 km) is an increased use of night trains. The time and money cost of travel is then compensated for by saving the cost of hotel accommodation.”

The two EEA reports does not bring any new facts to the issue of “level playing field”. What could be a very precise figure to bring to daylight is this one:

The average price a transport operator pays per energy unit (for instance kilowatt-hour) to fuel an airplane in Europe and abroad (A1 jet fuel), compared with the price to pay for electricity to an electric train in Europe.

By not providing such a number, it is not possible to have a real picture of the unfair situation. The ETS is not convincing, and will not alone bring level playing field to the transport sector.

The construction of infrastructure
A cradle to grave approach is not used in the studies and neither the impacts from constructions are. It is mentioned, that such figures could be nice to have, but data are not available. But one place constructions are mentioned:

“For new investment in rail to be environmentally beneficial, the environmental impacts from the construction of infrastructure must be compensated for by the reduced environmental impacts made possible by the opening of the new rail link.” (page 19) This is an essential point, when arguing for rail investments, that they are climate-wise sound and justified. But no-where in the EEA report is mentioned new constructions (or extentions) of airports or construction of new motorways. Why not? Can we understand that EEA of course will ague against all extentions of infrastructure related to environmental harming means of transport? It would suit EEA to go open and call for a stop to all investments that will lead to environmental damage.

This article is made by Poul Kattler, Back-on-Track, in Copenhagen, Denmark. It has been (and still is) subject to revisions according to dialogue with the EEA.

2 thoughts on “New comparison from European Environmental Agency (EEA) on Trains versus Planes”

  1. Pingback: Transportministeren skylder svar på, hvor enorm en klimabelastning lufthavnsudvidelsen giver - Bevar jordforbindelsen

  2. Interesting information, that has to be studied in more detail to be understood and used (or criticized ! ?).
    Peter Cornelius
    Head of regional subgroup for Berlin-Brandenburg of Passenger Organisation PRO BAHN

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